1. Field of the Invention
The invention concerns a vane extremity locking system.
2. Discussion of the Background
Turbo-engines include a certain number of vane stages, each stage possessing one radial extremity rigidly attached to the rotor or stator, and one opposing extremity bearing a ring whose main function is to delimit the longitudinal vein or path for the flow of gases. Thus, it is necessary to provide means to accurately and safely connect the ring to the extremities of the vanes to limit clearances and vibrations.
The U.S. Pat. No. 2,812,159 describes a technical solution where the ring is provided with holes allowing for passage of the extremities of the vanes. On the side of the ring opposite the vein, springs in the shape of folded back plates are disposed around the extremities of the vanes and pins traverse perforations situated at the end of the extremities so that the springs are compressed between the ring and the pins. It then becomes impossible to extract the vane extremities from the ring. As the vanes widen at the step on the side of the flow vein, it is no longer possible to drive them inside the ring. The springs are unable to slide over the ring as they fully surround the vane extremities, and finally the pins are retained in the reinforcements of the springs. Any accidental movement likely to disconnect the elements of the system is thus excluded. However, it is possible that in this technique vibrations do not appear during operation as the assemblies obtained are not particularly rigid. If it is intended to combat this drawback by using a more rigid spring, mounting shall be more difficult and it shall be necessary to overcome a higher spring elasticity force so as to be able to place the pins, this proving to be more awkward when the pins are introduced tangentially to the springs, that is with less space to work with.